• Title/Summary/Keyword: S/N Ratio

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An Adaptive Line Enhancer Using Lattice Notch Filters (격자형 노치 필터를 이용한 정현파 검출기)

  • 조남익;최종호;이상욱
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.24 no.4
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    • pp.719-726
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    • 1987
  • In this paper, an adaptive IIR (infinite impulse response) notch filter of lattice type is constructed and its adaptation algorithm is proposed for the detection and retrieval of a sine wave signal embedded in noise. A modified method which adapts only one coefficient of the filter is also suggested. All these methods adapt the coefficients while keepting the poles of the filter inside the unit circle on z-plane, and thus they satisfy the condition on the stability of the IIR filter after it has converged. To investigate the convergence characteristics of these methods such as convergence speed and output S/N ratio, intensive computer simulation has been performed by varying the frequency of the sine wave and the input S/N ratio. And the results of the simulation have been compared to those of Rao and Kung's which shows relatively fast convergence speed. The methods proposed here, especially the second one. shows faster convergence speed and higher output S/N ratio than the Rao and Kung's.

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Fatigue Limit of Copper Film (동 박막의 피로한도)

  • Huh, Yong-Hak;Kim, Dong-Jin;Lee, Hae-Moo;Hong, Sung-Gu;Park, Jun-Hyub
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.10
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    • pp.1158-1162
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    • 2009
  • Fatigue limit of the copper film coated by Sn was estimated using Goodman diagram and Gerber diagram. To obtain the high cycle fatigue life curve, S-N curve, of the film, the high cycle fatigue test was carried out by applying the constant amplitude load to the film specimen with three different stress ratio of 0.05, 0.3 and 0.5 and the frequency of 40 Hz at room temperature in air. The free-standing film specimen 15.26${\mu}m$ thick was fabricated by etching process. The fatigue limits and S-N curves at the respective stress ratios were determined from the experimental works. It was shown that the S-N curves were dependent on the stress ratio and the fatigue limit was increased with decreasing the stress ratio. The dependency of the fatigue behavior was presented in empirical relationship. Using these relationships, the fatigue limit was predicted.

Effect of $NO_3-N$ : $NH_4-N$ Ratio in Nutrient Solution on Growth, Yield and Fruit Quality of Strawberry 'Akihime' in Hydroponic System (딸기 수경재배에서 $NO_3-N$$NH_4-N$의 비율이 '장희(章姬)'의 생육, 수량 및 과실의 품질에 미치는 영향)

  • Jun, Ha-Joon;Hwang, Jin-Gyu;Son, Mi-Ja;Yoon, Hae-Suk
    • Journal of Bio-Environment Control
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    • v.18 no.1
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    • pp.40-45
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    • 2009
  • The experiment has investigated the effects of growth, yield, fruit quality and cation absorption of strawberry 'Akihime' in different $NO_3-N:NH_4-N$ ratio in nutrient solution. $NO_3-N:NH_4-N$ ratios were 5.5:0, 4.0:1.5 and $3.0:2.5me{\cdot}L^{-1}$. As the ratio of $NH_4-N$ increased, pH was decreased by $5.0{\sim}6.0$ and EC sustained $0.8{\sim}1.0dS{\cdot}m^{-1}$ during experiment. Though in high $NH_4-N$ ratio of $3.0:2.5me{\cdot}L^{-1}$, the absorption of cations(K, Ca and Mg) was not inhibited. Treatment in contained $NH_4-N$ showed a tendency of increasing of petiole length and leaf width. The fruit length, fruit width, fruit weight and soluble solids were not significantly different. Yield per plant was lowest in $4.0:1.5\;me{\cdot}L^{-1}$, of $NO_3-N:NH_4-N$ ratio. Malformation fruit has not shown during the whole growth period.

A study on TCR characteristic of $TaN/Al_{2}O_{3}$ thin film resistors ($TaN/Al_{2}O_{3}$ 박막 저항소자 개발에 관한 연구)

  • Kim, I.S.;Cho, Y.R.;Min, B.K.;Song, J.S.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.05b
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    • pp.82-85
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    • 2002
  • In recent years, the tantalum nitride(TaN) thin-film has been developed for the electronic resistor and capacitor. In this papers, this study presents the surface profile and sheet-resistance property relationship of reactive-sputtered TaN thin film resistor processed by buffer of Ti and Cr on alumina substrate. The TCR properties of the TaN films were discussed in terms of reactive gas ratio, ratio of nitrogen, crystallization and thin films surface morphology due to annealing temperature. It is clear that the TaN thin-films resistor electrical properties are low TCR related with it's buffer layer condition. Ti buffer layer thin film resistor having a good thermal stability and lower TCR properties then Cr buffer expected for the application to the dielectric material of passive component.

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A Study on Quantitative Measurements of Equivalence Ratio in Constant Volume Chamber Using UV Laser Raman Scattering (UV Laser Raman Scattering을 이용한 정적 연소기내 분사된 연료의 정량적 당량비 측정에 관한 연구)

  • Jin, S.H.;Heo, H.S.;Kim, G.S.;Park, K.S.
    • Journal of ILASS-Korea
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    • v.3 no.4
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    • pp.35-42
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    • 1998
  • Laser Raman scattering method has been applied to measure equivalence ratio of methane/air and propane/air mixture in constant volume combustion chamber. We used high power KrF excimer laser$(\lambda=248nm)$ and a high gain ICCD camera to capture low intensity Raman signal. Raman shifts and Ram cross-sections of $H_2,\;O_2,\;N_2,\;CO_2,\;CH_4\;and\;C_3H_8$ were measured precisely. Our results showed an excellent agreement with other groups. Mole fraction measurement of $O_2\;and\;N_2$ from air showed that $O_2\;:\;N_2$ = 0.206 : 0.794. We used constant volume combustion chamber and gas injector which is operated at $5\sim10barg$. Methane and propane are used as a fuel. 50 Raman signal are obtained and ensemble averaged for measurement of equivalence ratio. Our measured results showed that the equivalence ratio of fuel/air mixture is reasonable at ${\pm}5%$ error range.

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A Study on the Protection Ratio of GPS (GPS 보호비 연구)

  • Yu, Byeong-Jae;Shim, Yong-Sup;Cho, Hyun-Mook;Lee, Il-Kyoo;Hong, Heon-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.3A
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    • pp.296-301
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    • 2011
  • GPS(Global Positioning System) service is more important than other wireless services. The GPS is necessary protected from any other interference signals. Therefore, GPS protection ratio was calculated on the basis of bit error rate(BER) in this paper. Simulation results show that the allowable maximum interference power is -190 dBm/Hz and the ratio of interference to noise(I/N) is -16 dB. The achieved protection ratio is available to be applied as the protection criteria of GPS in considering the implementation margin of 4 dB. As a result, the proposed protection ratio of GPS is expected to give standard for a stable GPS service.

A Study on Easing Contraction made by different angles About angles on the sleeve cap curve line (재단각도 변화에 따른 오그림에 관한 연구 -소매산둘레선상의 각도를 중심으로-)

  • 이명희;최석철
    • Journal of the Korean Society of Clothing and Textiles
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    • v.22 no.1
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    • pp.41-48
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    • 1998
  • An investigation made of the easing contraction ratio according to sewing conditions (eased seam angle; 0$^{\circ}$ 20$^{\circ}$ 30$^{\circ}$ 45$^{\circ}$ 60$^{\circ}$ 70$^{\circ}$ 90$^{\circ}$, stitch density; 38 stitches/3 cm(N1.0), 26 stitches/ 3 cm(N1.5), 19 stitches/3 cm(N2.0), 14 stitches/3 cm(N2.5), 12 stitches/3 cm(N3.0), thread; sp 60' s/2) by lockstitch industrial sewing machine with shirring foot. The results abstained were as follows: 1. The lower the stitch density , the higher the easing contraction ratio. 2. The easing contraction ratio at 0$^{\circ}$ and 90$^{\circ}$ were lower than bias angles (20$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$, 60$^{\circ}$, 70$^{\circ}$). 3. As the results of visual test, the maximum easing conditions were Fl -0$^{\circ}$.20$^{\circ}$.30$^{\circ}$.45$^{\circ}$-12 stitches/3 cm(N3.0), 60$^{\circ}$. 70$^{\circ}$. 90$^{\circ}$-14 stitches/3 cm(N2.5), F2 -0$^{\circ}$. 20$^{\circ}$.30$^{\circ}$.60$^{\circ}$.70$^{\circ}$.90$^{\circ}$-19 stitches/ 3 cm(N2.0), 45$^{\circ}$ -14 stitches/3 cm(N2.5), and F3 -0$^{\circ}$.20$^{\circ}$.30$^{\circ}$.45$^{\circ}$.60$^{\circ}$.70$^{\circ}$.90$^{\circ}$-19 stitches/3 cm (N2.0). 4. Approximately easing contraction ratio was obtained as 2.0% (N1.0)~ 10.2% (N3.0) in F1, 6.7% (N1.0)~ 15.7% (N2.0) in F2, and 5.2% (N1.0)~ 12.1% (N2.0) in F3, according to different angles on the sleeve cap curve line. 5. As a resets of SPSS PC) statistics analysis, it confirmed the relations which were observed between easing contration ratio and stitch density, and easing contraction ratio was correlated with bending properties.

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Preparation and Properties of Na-Ca-Si-O-N System Oxynitride Glasses (Na-Ca-Si-O-N계 Oxynitride Glass의 제조 및 특성)

  • 이종호;이용근;최세영
    • Journal of the Korean Ceramic Society
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    • v.30 no.2
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    • pp.85-92
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    • 1993
  • Oxynitride glasses in Na-Ca-Si-O-N system were prepared by melting at 135$0^{\circ}C$ for 2 hours in N2 gas. The effects of Si/Na mole ratio and the various Si3N4 contents were investigated. Stable oxynitride glasses can be obtained up to 9wt.% Si3N4 content in case the Si/Na mole ratio was 2.12 and 1.62, but $\beta$-Si3N4 was precipitated at 9wt.% Si3N4 content in case the Si/Na mole rtio was 1.12. Density (p), chemical durability, hardness (Hv), and fracture toughness (KIC) increased with increasing Si3N4 content. In cae the Si/Na mole ratio was 1.12, the increment of properties was remarkable but hardness and fracture toughness did not increase no longer owing to precipitation of $\beta$-Si3N4.

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Study on residual stress characteristics according to the substrate type and V/III ratio during GaN growth by HVPE (HVPE 법을 통한 GaN 성장 시 기판 종류 및 V/III 비에 따른 잔류 stress 특성 연구)

  • Lee, Joo Hyung;Lee, Seung Hoon;Lee, Hee Ae;Kang, Hyo Sang;Oh, Nuri;Yi, Sung Chul;Lee, Seong Kuk;Park, Jae Hwa
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.30 no.2
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    • pp.41-46
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    • 2020
  • The characteristics of the residual stress on the types of the substrate was investigated with adjusting the V/III ratio during GaN growth via the HVPE method. GaN single crystal layers were grown on a sapphire substrate and a GaN template under the conditions of V/III ratio 5, 10, and 15, respectively. During GaN growth, multiple hexagonal pits in GaN single crystal were differently revealed in accordance with growth condition and substrate type, and their distribution and depth were measured via optical microscopy(OM) and white light interferometry(WLI). As a result, it was confirmed that the distribution area and depth of hexagonal pit tended to increase as the V/III ratio increased. Moreover, it was found that the residual stress in GaN single crystal decreased as the distribution area and depth of the pit increased through measuring micro Raman spectrophotometer. In the case of GaN growth according to substrate type, the GaN on GaN template showed lower residual stress than the GaN grown on sapphire substrate.

Functional Monomers and Polymers (Ⅰ). Polymerization of Acryloyl-Type Monomer Containing Lactam Ring (관능성 단량체 및 중합체 (제1보). Lactam 고리를 함유하고 있는 Acryloyl 형 단량체의 중합)

  • S. K. Noh;G. S. Sur;Sam K. Choi
    • Journal of the Korean Chemical Society
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    • v.24 no.1
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    • pp.64-72
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    • 1980
  • The synthesis of N-acrylylpyrrolidone has been carried out by the reaction of pyrrolidone and acrylyl chloride. The study on the copolymer of N-acrylylpyrrolidone and styrene is attempted.The copolymerization of N-acrylylpyrrolidone and styrene is carried out in benzene.Monomer reactivity ratio of N-acrylylpyrrolidone and styrene was calculated by Fineman and Ross equation. It is observed that the copolymer of N-acrylylpyrrolidone and styrene has random distributed acyl-lactam function on the vinyl polymer backbone.

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